Basically all lineal titles and number-one rankings are aligned with the UFC titles these days. However, there are a few key exceptions. One of those exceptions is the lineal strawweight title, which will be on the line at Rizin 18 this weekend.
#1 SW Haruo Ochi enters the event as the top-ranked fighter in the division, which Fight Matrix defines as 121.9 lbs and below. His opponent for the night will be UFC veteran #3 SW Jarred Brooks, who previously made a name for himself on the strawweight scene before moving up to flyweight to fight in the UFC.
Ochi dropped to strawweight in 2015 after competing at higher weight classes. In 2017 he captured the Deep strawweight title with a victory over Kanta Sato. A year later he picked up the biggest win of his career over #11 SW Mitsuhisa Sunabe at Rizin 13. In the process he took over the number-one spot at strawweight and claimed the lineal title. Sunabe had been undefeated since 2011 and was the strawweight King of Pancrase.
Brooks was a nationally ranked high school wrestler who was never really able to make it work on the collegiate level. Instead, he launched an MMA career in 2014. In his eight professional fight, he defeated veteran #23 SW Junji Ito and entered the strawweight rankings at number three. He fought once more in the division, scoring a victory over Jun Nakamura under the Pancrase banner, before moving up to flyweight to sign with the UFC. During his run in the UFC, he went 2-2 with victories over #31 FLW Eric Shelton and #34 FLW Roberto Sanchez. The promotion then released him as part of their ill conceived and ultimately unsuccessful plan to eliminate the flyweight division.
Considering the issues that the flyweight division has had getting over in the U.S., it seems unlikely that the strawweight division will ever really make a ton of headlines. However, the WBA, WBC, IBF and WBO all sponsor multiple boxing divisions under 125 pounds, so there is still a chance that the strawweight division could flourish on the international scene.